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08 January 2012

Identifying Files that don’t have an Extension

If a file doesn’t have an extension, you can still identify the format of
that file from its signature. All known file types have a standard and unique
signature and this data is stored in the file itself. There are programs that
can read this signature and determine the file format even if the extension is
missing from the file name.

The most popular program in the category of file identifiers is TrIDNet.
First download and unzip the TrIDNet utility and the associated XML definition
files in the same directory. Then open the TrIDNet.exe file, press the “Rescan
Defs” button to load the file signatures (you only need to do this once) and
then drag-drop any unknown files that you wish to analyze.
It will show the different file types that match with the file’s signature.
Do remember to rename
the files after identification (press F2, prefix a dot with the extension).